The development of innovative measurement and analysis tools enables new information on brain function, often allowing a range of novel questions to be addressed. Rapidly evolving metabolomics, peptidomics and proteomics tools facilitate new findings in both discovery and targeted modes. The Neuroproteomics and Neurometabolomics Center on Cell-Cell Signaling provides high-end 'omics-scale characterization of the small molecules, peptides and proteins for samples obtained from brain sub-regions like defined nuclei and even specific single cells. Our sampling methods allow molecular localization via discrete cell isolation, mass spectrometry imaging, measurement of activity dependent release, and quantitation of level changes as a function of exposure to drugs. We then characterize the most important molecular targets in these samples using metabolomics, peptidomics and proteomics via a broad array of mass spectrometry-based technologies. Finally, we provide the critical expertise for capturing the value of data via expert bioinformatics support that integrates disparate data types, develops advanced analytical approaches for complex metabolomics and proteomic experiments, and provides community support through several web platforms. At the beginning of the next granting period, we will be supporting an initial group of 17 major users representing 23 separately funded research projects across the fields of neuroscience, including projects targeting neuropeptides, transmitters and proteins that are involved in multiple aspects of drug escalation, exposure and addiction. We also will address fundamental questions of neuron/glia communication, dendritic protein expression and neuronal plasticity. The Neuroproteomics and Neurometabolomics Center on Cell- Cell Signaling is divided into three scientific cores: Sampling and Separation, Molecular Profiling and Characterization, and Bioinformatics and Systems Biology (plus an Administrative Core). The high level of synergy between the neuroscientists and technologists affiliated with the Center ensures progress in our broad suite of supported research projects, and promises continued advancements in the knowledge of how systems of neurons interact in both the healthy nervous system and upon exposure to drugs of abuse Lastly, a series of outreach initiatives assures that our protocols and approaches are broadly available to the appropriate scientific communities.